A common method for forming golf shafts from fiber/resin composite materials, is to wrap fiber impregnated fiber around hard tooling in the form of a mandrel which defines the interior dimensions of the shaft. The fiber is compacted during the winding, by using, for example, rolling tables, and pressure may also be applied by a shrinkable tape wrapped around the mandrel. The advantage of these systems is that the shape and dimensions of uncured resin/fiber preform as it is wound or formed on the mandrel closely approximate the final product. There is little movement of the fiber during cure of the composite, thus the positions of the reinforcing fibers can be controlled well. However, these methods have the disadvantage that only low compaction pressures can only be applied if oven cure of the composite is used. Pressures can be applied using autoclave equipment, but this is not economically feasible for most applications. High compaction pressures are required to form high performance composites that are of light weight but have high strength. In addition, since the tooling must be removable after curing of the part, complex profiles which would trap the rigid interior mandrel pieces cannot be made with this method. Accordingly, this method is limits the shafts to lower structural performance, since the composite is made with low compaction pressure, and this method is also limited to relatively simple tapered shapes.
Another approach is disclosed in French patent applications 90 15387 and 90 15388. In this method a bladder is formed upon a hard metal mandrel. Resin impregnated fiber is formed around the bladder and the assembly placed into female tooling. The bladder is inflated at the base of the mandrel to expand the impregnated fiber into the tooling. This method has several disadvantages. The method disclosed is limited to shapes where the rigid mandrel can be removed from the cured part, i.e., is not trapped by the profile of shape of the part. Conversely, the impregnated fiber material in the preform would have to move substantially from its initial as formed or rolled shape to form a complex shape, which would likely displace the fibers and possibly compromise the properties of the final part. In addition, creation of a complex shape with, for example, a bulge would have entrances precluding removal of a rigid mandrel. Furthermore, the bladder used in this process is a thin walled latex rubber material formed by dipping the mandrel. Accordingly, the bladder necessarily is thin walled and has essentially the shape of the mandrel. In addition, the bladder such a bladder would not be durable and be capable of repeated use. The process of the French patent application also necessarily leaves the rigid metal mandrel inside the part during cure. This has the disadvantage of substantially slowing the rates of heat up and cool down during cure, because the large thermal mass of the metallic mandrel is thermally insulated by the relatively low conductivity composite material. Also, a large number of rigid mandrels are needed to flow through the entire bladder fabrication, shaft fabrication process, substantially increasing capital equipment costs.